EVA胶粉改性水下抗分散修补砂浆的制备与性能研究

摘要

采用醋酸乙烯-乙烯共聚物(EVA)胶粉、硫铝酸盐水泥、普通硅酸盐水泥、砂、聚丙烯酰胺和高效减水剂等制备了改性水下抗分散修补砂浆,研究了EVA胶粉对修补砂浆水下粘结强度、水下抗折和抗压强度、流动性及水下凝结时间的影响,通过扫描电镜(SEM)观察了EVA胶粉改性砂浆的微观形貌.结果表明:EVA胶粉显著提高了修补砂浆的水下粘结强度和抗折抗压强度.与未掺EVA的修补砂浆相比,掺加8%EVA胶粉的修补砂浆28 d水下粘结强度提高了50%、抗折强度提高了30%.SEM分析表明,EVA胶粉在砂浆中形成了聚合物膜,并且随着EVA胶粉掺量的增加,逐渐形成连续结构的聚合物膜.%An underwater dispersion resistant repair mortar was prepared with vinyl acetate ethylene copolymer(EVA)pow-der,sulphoaluminate cement,Portland cement,sand,polyacrylamide and superplasticizer. Effect of EVA powder on underwater adhe-sion strength,compressive strength,flexural strength,flow resistance and setting time of the underwater dispersion resistant repair mortar was investigated,and the microstructure of the mortar modified by EVA powder was observed by scanning electron mi-croscopy(SEM). The results indicated that the underwater adhesion strength,compressive strength and flexural strength of the re-pair mortar was significantly improved by the EVA powder. Compared with the repair mortar without EVA,the adhesive strength of 28 d increases by 50% and the flexural strength increases by 30% by the addition of 8%EVA powder. SEM of the repair mortar showed that the EVA gradually formed a continuous polymer film with the increase of EVA powder content.